1. Field of the Invention
This invention relates to a Raman spectroscopy method, a Raman spectroscopy system and a Raman spectroscopy device and more particularly to a Raman spectroscopy device for increasing Raman scattering.
2. Description of the Related Art
The Raman spectroscopy method is a method where a spectrum (Raman spectrum) is obtained by separating scattering light obtained by projecting light of a single wavelength onto a material and light (Raman scattering light) having a wavelength different from that of the projected light is detected. Since being very weak, the Raman scattering light is generally difficult to detect. However, it has been reported that the intensity of the Raman scattering light is increased to 104 to 106 when light is projected onto the material adsorbed on the surface of metal. Especially it has been known that when metal particles in the order of nanometers are distributed on the surface on which the material is adsorbed, the Raman scattering light is greatly increased. See, for instance, “Brilliant Optical Properties of Nanometric Noble Metal Spheres, Rods, and Aperture Arrays”, Peter C. Andersen and Kathy L. Rowlen, Applied Spectroscopy, Volume 56, Number 5, 2002. The increase of the Raman scattering light is said to be due to local plasmon resonance. That is, it is said that strong electric fields are generated around metal particles when the free electrons in the metal particles vibrate resonating with an electric field of light, and the Raman scattering light is increased under the influence of the electric fields.